Class FormFields

java.lang.Object
java.util.AbstractCollection<FormField>
FormFields
All Implemented Interfaces:
Iterable<FormField>, Collection<FormField>
public final class FormFields extends AbstractCollection<FormField>
Represents a collection of FormField objects.

This class provides the main interface for the analysis and manipulation of form controls. A FormFields object is a collection of FormField objects, with each form field consisting of a group of form controls having the same name.

The functionality provided by this class can be used to accomplish two main tasks:

  1. Modify the submission values of the constituent form controls for subsequent output in an OutputDocument.

    The methods available for this purpose are:
    List<String> getValues(String fieldName)
    Map<String,String[]> getDataSet()
    void clearValues()
    void setDataSet(Map<String,String[]>)
    boolean setValue(String fieldName, String value)
    boolean addValue(String fieldName, String value)

    Although the FormField and FormControl classes provide methods for directly modifying the submission values of individual form fields and controls, it is generally recommended to use the interface provided by this (the FormFields) class unless there is a specific requirement for the lower level functionality.

    The display characteristics of individual controls, such as whether the control is disabled, replaced with a simple value, or removed altogether, can only be set on the individual FormControl objects. See below for information about retrieving a specific FormControl object from the FormFields object.

  2. Convert data from a form data set (represented as a field data set) into a simple array format, suitable for storage in a tabular format such as a database table or .CSV file.

    The methods available for this purpose are:
    String[] getColumnLabels()
    String[] getColumnValues(Map)
    String[] getColumnValues()

    The Util class contains a method called outputCSVLine(Writer,String[]) which writes the String[] output of these methods to the specified Writer in .CSV format.

    The implementation of these methods makes use of certain properties in the FormField class that describe the structure of the data in each field. These properties can be utilised directly in the event that a form data set is to be converted from its normal format into some other type of data structure.

To access a specific FormControl from a FormFields object, use:

The term field data set is used in this library to refer to a data structure consisting of a set of names (in lower case), each mapped to one or more values. Generally, this is represented by a data type of java.util.Map<String,String[]>, with the keys (names) being of type String and the values represented by an array containing one or more items of type String. A field data set can be used to represent the data in an HTML form data set.

FormFields instances are obtained using the FormFields(Collection formControls) constructor or by calling the Segment.getFormFields() method.

The case sensitivity of form field names is determined by the static Config.CurrentCompatibilityMode.FormFieldNameCaseInsensitive property.

Examples:

  1. Write the data received from in the current ServletRequest to a .CSV file, and then display the form populated with this data: 

       Source source=new Source(htmlTextOfOriginatingForm);
   FormFields formFields=source.getFormFields();

   File csvOutputFile=new File("FormData.csv");
   boolean outputHeadings=!csvOutputFile.exists();
   Writer writer=new FileWriter(csvOutputFile,true);
   if (outputHeadings) Util.outputCSVLine(writer,formFields.getColumnLabels());
   Util.outputCSVLine(writer,formFields.getColumnValues(servletRequest.getParameterMap()));
   writer.close();

   formFields.setDataSet(servletRequest.getParameterMap());
   OutputDocument outputDocument=new OutputDocument(source);
   outputDocument.replace(formFields);
   outputDocument.writeTo(servletResponse.getWriter());

    See also the sample program FormFieldCSVOutput.

  2. Replace the initial values of controls in the form named "MyForm" with new values: 

       Source source=new Source(htmlText);
   Element myForm=null;
   List formElements=source.getAllElements(Tag.FORM);
   for (Iterator i=formElements.iterator(); i.hasNext();) {
     Element formElement=(Element)i.next();
     String formName=formElement.getAttributes().getValue("name");
     if ("MyForm".equals(formName)) {
       myForm=form;
       break;
     }
   }
   FormFields formFields=myForm.getFormFields();
   formFields.clearValues(); // clear any values that might be set in the source document
   formFields.addValue("Name","Humphrey Bear");
   formFields.addValue("MailingList","A");
   formFields.addValue("MailingList","B");
   formFields.addValue("FavouriteFare","honey");
   OutputDocument outputDocument=new OutputDocument(source);
   outputDocument.replace(formFields);
   String newHtmlText=outputDocument.toString();

    See also the sample program FormFieldSetValues.

  3. Change the display characteristics of individual controls: 

       Source source=new Source(htmlText);
   FormFields formFields=source.getFormFields();
   // disable some controls:
   formFields.get("Password").getFormControl().setDisabled(true);
   FormField mailingListFormField=formFields.get("MailingList");
   mailingListFormField.setValue("C");
   mailingListFormField.getFormControl("C").setDisabled(true);
   mailingListFormField.getFormControl("D").setDisabled(true);
   // remove some controls:
   formFields.get("button1").getFormControl().setOutputStyle(FormControlOutputStyle.REMOVE);
   FormControl rhubarbFormControl=formFields.get("FavouriteFare").getFormControl("rhubarb");
   rhubarbFormControl.setOutputStyle(FormControlOutputStyle.REMOVE);
   // set some controls to display value:
   formFields.setValue("Address","The Lodge\nDeakin  ACT  2600\nAustralia");
   formFields.get("Address").getFormControl().setOutputStyle(FormControlOutputStyle.DISPLAY_VALUE);
   FormField favouriteSportsFormField=formFields.get("FavouriteSports");
   favouriteSportsFormField.setValue("BB");
   favouriteSportsFormField.addValue("AFL");
   favouriteSportsFormField.getFormControl().setOutputStyle(FormControlOutputStyle.DISPLAY_VALUE);
   OutputDocument outputDocument=new OutputDocument(source);
   outputDocument.replace(formFields); // adds all segments necessary to effect changes
   String newHtmlText=outputDocument.toString();

    See also the sample program FormControlDisplayCharacteristics.

See Also:

  • Constructor Details

  • Method Details

    • getCount

      public int getCount()
      Returns the number of FormField objects.
      Returns:
      the number of FormField objects.

    • size

      public int size()
      Returns the number of FormField objects.

      This is equivalent to getCount(), and is necessary to for the implementation of the java.util.Collection interface.

      Specified by:
      size in interface Collection<FormField>
      Specified by:
      size in class AbstractCollection<FormField>
      Returns:
      the number of FormField objects.

    • get

      public FormField get(String fieldName)
      Returns the FormField with the specified name.

      The case sensitivity of the fieldName argument is determined by the static Config.CurrentCompatibilityMode.FormFieldNameCaseInsensitive property.

      Parameters:
      fieldName - the name of the FormField to get.
      Returns:
      the FormField with the specified name, or null if no FormField with the specified name exists.

    • iterator

      public Iterator<FormField> iterator()
      Returns an iterator over the FormField objects in the collection.

      The order in which the form fields are iterated corresponds to the order of appearance of each form field's first FormControl in the source document.

      If this FormFields object has been merged with another, the ordering is no longer defined.

      Specified by:
      iterator in interface Collection<FormField>
      Specified by:
      iterator in interface Iterable<FormField>
      Specified by:
      iterator in class AbstractCollection<FormField>
      Returns:
      an iterator over the FormField objects in the collection.

    • getValues

      public List<String> getValues(String fieldName)
      Returns a list of the field submission values of all the specified constituent form fields with the specified name.

      All objects in the returned list are of type String, with no null entries.

      This is equivalent to get(fieldName).getValues(), assuming that a field with the specified name exists in this collection.

      Parameters:
      fieldName - the name of the form field.
      Returns:
      a list of the field submission values of all the specified constituent form field with the specified name, or null if no form field with this name exists.
      See Also:

    • getDataSet

      public Map<String,String[]> getDataSet()
      Returns the entire field data set represented by the values of the constituent form fields.

      The values in the map returned by this method are represented as a string array, giving the map a format consistent with the javax.servlet.ServletRequest.getParameterMap() method.

      Only the names of form fields with at least one value are included in the map, meaning every String[] is guaranteed to have at least one entry.

      Iterating over the map keys returns them in the order of appearance in the source document.

      Returns:
      the entire field data set represented by the values of the constituent form fields.
      See Also:

    • clearValues

      public void clearValues()
      Clears the submission values of all the constituent form controls.
      See Also:

    • setDataSet

      public void setDataSet(Map<String,String[]> dataSet)
      Sets the submission values of all the constituent form controls to match the data in the specified field data set.

      The map keys must be String field names, with each map value an array of String objects containing the field's new values.

      The map returned by the javax.servlet.ServletRequest.getParameterMap() method has a suitable format for use with this method.

      All existing values are cleared before the values from the field data set are added.

      Any map entries with a null value are ignored.

      Parameters:
      dataSet - the field data set containing the new values of the constituent form fields.
      See Also:

    • setValue

      public boolean setValue(String fieldName, String value)
      Sets the field submission values of the constituent form field with the specified name to the single specified value.

      This is equivalent to get(fieldName).setValue(value), assuming that a field with the specified name exists in this collection.

      The return value indicates whether the specified form field "accepted" the value. A return value of false implies an error condition as either no field with the specified name exists, or the specified value is not compatible with the specified field.

      Parameters:
      fieldName - the name of the form field.
      value - the new field submission value of the specified field, or null to clear the field of all submission values.
      Returns:
      true if a field of the specified name exists in this collection and it accepts the specified value, otherwise false.

    • addValue

      public boolean addValue(String fieldName, String value)
      Adds the specified value to the field submission values of the constituent form field with the specified name.

      This is equivalent to get(fieldName).addValue(value), assuming that a field with the specified name exists in this collection.

      The return value indicates whether the specified form field "accepted" the value. A return value of false implies an error condition as either no field with the specified name exists, or the specified value is not compatible with the specified field.

      Parameters:
      fieldName - the name of the form field.
      value - the new field submission value to add to the specified field, must not be null.
      Returns:
      true if a field of the specified name exists in this collection and it accepts the specified value, otherwise false.

    • getColumnLabels

      public String[] getColumnLabels()
      Returns a string array containing the column labels corresponding to the values from the getColumnValues(Map) method.

      Instead of using the name of each constituent form field to construct the labels, the name of the first form control from each form field is used. This allows the labels to be constructed using the names with the original case from the source document rather than unsing the all lower case names of the form fields.

      See the documentation of the getColumnValues(Map) method for more details.

      Returns:
      a string array containing the column labels corresponding to the values from the getColumnValues(Map) method.
      See Also:

    • getColumnValues

      public String[] getColumnValues(Map<String,String[]> dataSet)
      Converts the data values in the specified field data set into a simple string array, suitable for storage in a tabular format such as a database table or .CSV file.

      The conversion is performed in a way that allows the multiple values of certain fields to be stored in separate columns, by analysing the possible form data sets that can be generated from the constituent form controls.

      The column labels and values are determined as follows:

      The sample program FormFieldCSVOutput demonstrates the use of this method and its output.

      Parameters:
      dataSet - a field data set containing the data to convert.
      Returns:
      the data values in the specified field data set in the form of a simple string array.
      See Also:

    • getColumnValues

      public String[] getColumnValues()
      Converts all the form submission values of the constituent form fields into a simple string array, suitable for storage in a tabular format such as a database table or .CSV file.

      This is equivalent to getColumnValues(getDataSet()).

      Returns:
      all the form submission values of the constituent form fields in the form of a simple string array.

    • getFormControls

      public List getFormControls()
      Returns a list of all the constituent form controls from all the form fields in this collection.
      Returns:
      a list of all the constituent form controls from all the form fields in this collection.

    • merge

      public void merge(FormFields formFields)
      Merges the specified FormFields into this FormFields collection. This is useful if a full collection of possible form fields is required from multiple source documents.

      If both collections contain a FormField with the same name, the resulting FormField has the following properties:

      NOTE: Some underlying data structures may end up being shared between the two merged FormFields collections.

    • getDebugInfo

      public String getDebugInfo()
      Returns a string representation of this object useful for debugging purposes.
      Returns:
      a string representation of this object useful for debugging purposes.

    • toString

      public String toString()
      Returns a string representation of this object useful for debugging purposes.

      This is equivalent to getDebugInfo().

      Overrides:
      toString in class AbstractCollection<FormField>
      Returns:
      a string representation of this object useful for debugging purposes.